1. Field of the Invention
The invention relates to a procedure for modernizing the control system of an elevator group.
2. Description of Related Prior Art
Finnish Patent Publication No. 68797 (Ovaska et al) presents a procedure for modernizing an elevator group. In greatly simplified terms, the procedure presented in said publication can be described as follows: A new group control system is installed in the machine room to control the old elevator controllers, which are connected to it using adapting computers. Next, the control functions of the individual elevators in the bank are modernized one elevator at a time. For this purpose, the elevator is disconnected from the group controller, the old control functions of the elevator as well as the adapting computer are replaced with a new elevator-specific set of control equipment, whereupon the elevator is connected directly to serve under the new group controller.
An article entitled "Overlays" by J. W. Fortune (Elevator World, September 1985) describes the overlay modernization on a general level. The article also presents a concept whereby the modernization proceeds in a stepwise manner, using a modular method. However, the concept is based on a type of overlay technology that is presented e.g. in FI 68797. Therefore, the method of modernization proposed in the above mentioned article is well suited for cases where an extensive modernization job is carried out completely at the same time, but its realistic implementation in a multi-stage modular modernization project would involve a large amount of work and expenses. This is because, using conventional parallel wiring, there would generally be a considerable amount of wiring installation work and temporary connections. The article also comprises a description of a case of "conventional" overlay modernization along the principles of the solution presented in the above-mentioned patent publication FI 68797.